You are the salt of the earth: but if the salt has lost its savor, how shall it be salted? it is thereafter good for nothing, but to be cast out, and to be trodden under foot of men.
All Commentaries on Matthew 5:13 Go To Matthew 5
John Chrysostom
AD 407
It is as a matter of absolute necessity that he commands all this. Why must you be salt? Jesus says in effect: “You are accountable not only for your own life but also for that of the entire world. I am sending you not to one or two cities, nor to ten or twenty, nor even to one nation, as I sent the prophets. Rather, I am sending you to the entire earth, across the seas, to the whole world, to a world fallen into an evil state.” For by saying, “You are the salt of the earth,” Jesus signifies that all human nature itself has “lost its taste,” having become rotten through sin. For this reason, you see, he requires from his disciples those character traits that are most necessary and useful for the benefit of all. The Gospel of Matthew, Homily